当前位置: 技术问答>linux和unix
求助关于操作系统的几个问题?
来源: 互联网 发布时间:2016-03-29
本文导语: 诚望大家翻译一下下面几问题的参考答案!!!! 1.一个进程如何引用不在其地址空间的对象? 答:The process address space provides a uniform mechanism for authorizing access to memory-mapped resources (especially executable memory...
诚望大家翻译一下下面几问题的参考答案!!!!
1.一个进程如何引用不在其地址空间的对象?
答:The process address space provides a uniform mechanism for authorizing access to memory-mapped resources (especially executable memory locations) according to the OS’s security policy. All other resources have a name that must appear in a distinct, shared name space: File names are an example of such a name space; email addresses are another example, and web URLs are a third example. When a process needs to access one of these resources that is not in its address space, it uses an appropriate shared (also sometimes called a global) address space.
2.为什么操作系统中进程描述表是一个静态数组,而不使用动态数据结构?
答:Here are a few reasons:
a. Dynamic data structures in the kernel are allocated from a system heap rather than from a heap in an address space (as is done with malloc()). OS designers do not like to depend on memory being available for the correct operation of the OS, since memory may get used up by some other kernel function.
b. By fixing the number of processes that can exist, the rest of the system can be designed by knowing that maximum value (even if it is a compile-time parameter). It implicitly puts a bound on the total load that can be placed on the system.
c. It is much faster to access the data in the process descriptors.
3.分时技术对操作系统做出了什么贡献?
答: Timesharing stimulated development of the idea of processes, memory management, scheduling, and protection/security technology. (This is a slightly more comprehensive set of things than are in the figure in the chapter).
4.嵌入式系统对现代操作系统有什么贡献?
答:Embedded systems is the area where real-time support was refined and made to work well. The real-time technology in contemporary operating systems is generally from embedded systems.
1.一个进程如何引用不在其地址空间的对象?
答:The process address space provides a uniform mechanism for authorizing access to memory-mapped resources (especially executable memory locations) according to the OS’s security policy. All other resources have a name that must appear in a distinct, shared name space: File names are an example of such a name space; email addresses are another example, and web URLs are a third example. When a process needs to access one of these resources that is not in its address space, it uses an appropriate shared (also sometimes called a global) address space.
2.为什么操作系统中进程描述表是一个静态数组,而不使用动态数据结构?
答:Here are a few reasons:
a. Dynamic data structures in the kernel are allocated from a system heap rather than from a heap in an address space (as is done with malloc()). OS designers do not like to depend on memory being available for the correct operation of the OS, since memory may get used up by some other kernel function.
b. By fixing the number of processes that can exist, the rest of the system can be designed by knowing that maximum value (even if it is a compile-time parameter). It implicitly puts a bound on the total load that can be placed on the system.
c. It is much faster to access the data in the process descriptors.
3.分时技术对操作系统做出了什么贡献?
答: Timesharing stimulated development of the idea of processes, memory management, scheduling, and protection/security technology. (This is a slightly more comprehensive set of things than are in the figure in the chapter).
4.嵌入式系统对现代操作系统有什么贡献?
答:Embedded systems is the area where real-time support was refined and made to work well. The real-time technology in contemporary operating systems is generally from embedded systems.
|
1.进程地址空间根据操作系统的安全策略提供了统一的访问内存表资源(特别是可执行内存地址)机制。所有其它资源都有一个明确的名称来共享名称空间。文件名就是此名称空间的例子之一,电子邮件地址则是另一例子,还有webURLS(网络资源定位器)乃第三个例子。当一个进程需要访问这些资源当中时,但这些资源又不在其地址空间范围内,则它使用一个适当的共享地址空间(通常叫全局共享)。
2.有如下几个原因:
a.内核中的动态数据结构由系统堆栈分配而来的(通常用malloc()函数完成),而不是地址空间的一个堆栈。操作系统
的设计者不喜欢由操作系统来判断内存的可用性,则内存可能会被内核里的其它函数用尽。
b.通过固定的进程号,系统的其它部分的设计均知道进程数的最大值(尽管这是编译时的参数)。它隐含地给一个值让它能在系统中存放。
c.通过进程描述符能更快的访问数据。
3.分时系统促进了多进程开发思想,内存管理,作业管理和安全/保护技术的发展。
4.嵌入式系统是精制、稳定的实时系统。当代实时操作系统技术源于嵌入式系统。
呵呵,好久没看E语了,随手翻译一下,翻译不对的地方请见谅。
2.有如下几个原因:
a.内核中的动态数据结构由系统堆栈分配而来的(通常用malloc()函数完成),而不是地址空间的一个堆栈。操作系统
的设计者不喜欢由操作系统来判断内存的可用性,则内存可能会被内核里的其它函数用尽。
b.通过固定的进程号,系统的其它部分的设计均知道进程数的最大值(尽管这是编译时的参数)。它隐含地给一个值让它能在系统中存放。
c.通过进程描述符能更快的访问数据。
3.分时系统促进了多进程开发思想,内存管理,作业管理和安全/保护技术的发展。
4.嵌入式系统是精制、稳定的实时系统。当代实时操作系统技术源于嵌入式系统。
呵呵,好久没看E语了,随手翻译一下,翻译不对的地方请见谅。
|
1.处理地址空间对进入对记忆被映射的资源提供一个一致的机制(特别是可执行的存储单元)的批准的入口根据操作系统的安全策略。 其他资源有必须出现于一个分明,共有的名空间的一个名字: 文件名字是这样一个名空间的例子; 电子邮件是另一个例子,并且网URL是第三个例子。 当过程需要访问不在它的地址空间这些资源的之一时,它使用一个适当的共有的(有时也叫全球性)地址空间。
2.a. 动态数据结构是从系统堆中被分配的而不是从地址空间的堆(就像malloc ()一样)。 因为内存也可能被其他内核函数调用, 操作系统设计师不喜欢取决于是的内存可利用的为操作系统的正确操作。
b. 通过固定可能存在过程的数量,系统的其余可以通过知道那个最大价值设计(即使它是一个编译时间的参量)。 它在系统可以被安置的总装载上隐含地把区域放。
c. 它是更加快速的访问数据描述符。
3.分时操作刺激发展了安全保护技术,进程处理思想,内存和日程管理
4.嵌入系统是一个精简的实时操作系统并且有好工作性能。 在当代操作系统的实时技术通常是从嵌入系统。
时间匆忙,翻译比较粗糙,勿怪
2.a. 动态数据结构是从系统堆中被分配的而不是从地址空间的堆(就像malloc ()一样)。 因为内存也可能被其他内核函数调用, 操作系统设计师不喜欢取决于是的内存可利用的为操作系统的正确操作。
b. 通过固定可能存在过程的数量,系统的其余可以通过知道那个最大价值设计(即使它是一个编译时间的参量)。 它在系统可以被安置的总装载上隐含地把区域放。
c. 它是更加快速的访问数据描述符。
3.分时操作刺激发展了安全保护技术,进程处理思想,内存和日程管理
4.嵌入系统是一个精简的实时操作系统并且有好工作性能。 在当代操作系统的实时技术通常是从嵌入系统。
时间匆忙,翻译比较粗糙,勿怪